While you can get the plan information (along with downloads) on the Whole30 web site the first part of the book is "science-y stuff" which goes into detail on how your body reacts to food and what keeps it on an even keel (without sugar spikes). The second part gives you more info. on what to eat along with meal plans and recipes.
I intend to take the 30 day challenge and you can see my progress over on Less of Me. The plan is not a weight loss diet, focusing more on a healthy life style, but nevertheless participants have reported high weight loss.